Engines, for example vehicle engines, have included aspirators and/or check valves for a long time. Typically, the aspirators are used to generate a vacuum that is lower than engine manifold vacuum by inducing some of the engine air to travel through a venturi. The aspirators may include check valves therein or the system may include separate check valves. When the check valves are separate, they are typically included downstream between the source of the vacuum and the device using the vacuum.
In engines that have a brake boost system, conditions exist that may make it difficult for a check valve to seal effectively. This is undesirable, and new check valves are needed to provide more efficient sealing.